For the treatment of the skin with light, e.g. the treatment of Psoriasis Vulgaris, full body treatments are used. Although this guarantees that e.g. plaques of Psoriasis Vulgaris are treated, a large area of healthy skin is treated as well. Dependent on the kind of treatment, the effects of treating healthy skin can differ from seriously impacting a patient's health to less serious cosmetic effects such as hyper pigmentation.
It would be advantageous to enable specific skin sites to be selected and treated in order to minimize such side effects.